The intuitive idea behind a trait group is that there can be evolutionarily relevant structure within demes, such that organisms that belong to one part of the deme may well be subject to causal influences that do not extend to the deme as a whole.

After Theramenes 'execution, many citizens left the walled city: some regrouped in the distant and mountainous deme of Phyle, planning to topple the Thirty (among them was Socrates' childhood friend, Chaerephon); others went only as far as the Piraeus where “the Ten” (including Charmides) chosen by the Thirty were less effective at suppression than the Thirty themselves.

The Thirty, now increasingly referred to as an oligarchy, were also making contingency plans: they sent forces to secure the deme of Eleusis for themselves by putting to death the population on charges of supporting democracy